Hypothalamic Control of Eating

Question 1

Why do we stop eating

Answer 1

satiety

Question 2

Gastric stretch causes

Answer 2

decrease in food intake

Question 3

Gastric nutrient: sucrose –>

Answer 3

decreased food intake

Question 4

Intestinal nutrient: sucrose –>

Answer 4

decrease food intake

Question 5

liver factors via the portal vein senses Glucose and Free fatty acids –>

Answer 5

decreased food intake

Question 6

In gastric distention, mechanoreceptors - vagal afferents relay to what center which causes a decrease in food intake

Answer 6

Nucleus Tractus Solitarius (NTS)

[solitary nucleus in the medulla]

Question 7

Cholecytokinin (CCK) is a hormone that is released from the …

Answer 7

Duodenum

Question 8

Cholecytokinin (CCK) causes

Answer 8

increased gallbladder contraction –> release of bile –> fat digestion
increased pyloric constriction –> increased stomach activity
Increased gastric contractions –> stomach activity digestion

Question 9

______________ works on CCK receptors to increase excitation of vagal affernts (gastric mechanorecptors) which excites the NTS and decreased food intake

Answer 9

Cholecystokinin (CCK)

Question 10

This hormone in the stomach is increased by fasting and is orexigenic (increases appetite)

Answer 10

Ghrelin

Question 11

Prader-Willi Syndrome (deletion on chromosome 15)

Symptoms:

Answer 11

fetal hypotonia
mental retardation
obesity 
hyperphagia (excessive eating) 
hypogonadotropic hypogonadism (dcreased FSH and LH --> decreased gonadal function)

Question 12

hypothalamic control of eating short-term signals

Answer 12

gastric distention
cholecytokinin (CCK)
Ghrelin

Question 13

Hypothalamic control of eating long-term signals

Answer 13

Leptin

Question 14

Leptin - the ob protein - is released from ________ and causes a decrease in food intake

Answer 14

adipocytes

Question 15

Site of action for leptin

Answer 15

brainstem –> solitary nucleus

hypothalamus

Question 16

Hypothalamic Nuclei implicated in control of food intake

Answer 16

Lateral hypothalamic area (LHA)
Paraventricular nucleus (PVN)
Arcuate nucleus (ARC)

Question 17

Lateral hypothalamic area (LHA) lesion could cause

Answer 17

aphagia (cessation of eating)
aphagia due to damage to medial forebrain bundle
reduced motivation to eat (meso-limbic system –>DA)
reduced motor function

Question 18

In the solitary nucleus, this increases responsiveness to gastric stretch

Answer 18

leptin

Question 19

Lateral hypothalamic area (LHA)

Aphagia due to: loss of neurons that synthesze ________peptide

Answer 19

“orexigenic” OREXIN

Question 20

Activation of LHA –> causes release of ______ neurotransmitter into the brainstem

Answer 20

anabolic (increased eating, increased eating/growth)

Question 21

Paraventricular nucleus (PVN) neurons send axons to the brainstem to regulate food intake and causes _________

Answer 21

decrease in eating

Question 22

Activation of the Paraventricular nucleus (PVN) causes

Answer 22

release of “catabolic” neurotransmittor(s) in the brainstem which causes decrease in eating and growth

Question 23

Neurotransmitter released in the brainstem by the paraventricular nucleus

Answer 23

Corticotropin releasing hormone (CRH)

Question 24

two populations of neurons in the Arcuate nucleus (ARC)

Answer 24

Neuropeptide Y (NPY)
Melanocortin (POMC-derived peptide)

Question 25

Neuropeptide Y (NPY) neurons project to

Answer 25

PVN and LHA which increases eating

Question 26

Leptin acts in the ARC to inhibit

Answer 26

NPY neuronal activity (causes a decrease in food intake)

Question 27

Melanocortin (POMC-derived peptide) neurons project both to

Answer 27

PVN and to LHA

Question 28

Leptin acts in the ARC to activate

Answer 28

Melanocortin neuronal activity (causes decreased eating)

Question 29

Ghrelin acts in the ARC to increase

Answer 29

NPY neuronal activity (causes increased food intake)